1. Field of Invention
This invention relates to automatic rifles. More particularly, the present invention relates to the operating system of firearms in the AR15/M16 series of firearms. Specifically the herein described invention concerns the bolt carrier assembly for use in such firearms.
2. Prior Art
The AR15/M16 family of weapons and their derivatives to include indirect gas operated versions, have been in use by the military and civilian population for many years. An essential part of this firearms design is the bolt carrier which typically includes a bolt mounted in the carrier for axial sliding movement and rotation, a firing pin slidably mounted within the bolt and bolt carrier for restricted reciprocating axial movement, and a cam pin for producing relative rotation between the bolt and the bolt carrier. The bolt carrier is generally cylindrical in shape and is provided with a circular bore throughout its length. The bolt carrier also is provided with an opening on its top and bottom sides to allow the hammer to extend into the interior of the bolt carrier and strike the firing pin. There are also openings to mount a gas key, an opening which serves as a gas receiving port, and an opening to receive the cam pin in direct gas operated firearms. Indirect gas operated firearms, typically referred to as piston operated systems, replace the gas receiving port with a striking surface which varies between iterations. About the exterior of the bolt carrier are a series of usually four (4) lands and usually accompanying grooves which extend from the forward end of the bolt carrier (as it is mounted in the firearm) rearwardly for a distance of about one-half the length of the bolt carrier. A land can be defined as a raised portion on the exterior of the bolt carrier which contacts the interior surface of the upper receiver of the firearm. Such lands are generally equally spaced from one another about the exterior of the bolt carrier and are generally parallel to each other. The exterior surfaces of the lands make contact with the interior surface of the upper receiver of the firearm and serve to align the bolt carrier within the receiver. With the striking surface of indirect gas operated firearm being above the central axis of the bolt carrier a phenomenon known as carrier tilt occurs during the normal operation of the firearm. Carrier tilt can be defined as the rear of the carrier, or boss, tilting down when the striking surface has been contacted by the piston resulting in the rearward movement of the carrier being resisted when the now off axis carrier strikes the shelf of the firearms lower receiver housing. Eliminating carrier tilt would be a very desirable.
Firearms based on the AR15/M16 family are the primary weapon of choice for military units in the United States and abroad. Highly trained units from all branches of service often find themselves operating in aquatic conditions prior to coming on land. The inability of the AR15/M16 series of weapons to be fired when water is present in the operating system puts these war fighters in a compromising position. With the current AR15/M16 series of weapons, and their derivatives, the firearm must be drained of all water prior to being discharged. This is not convenient or practical for a war fighter who may come under fire immediately upon landing on a beach. Such situations are typically referred to as over the beach operations”. Incorporating features into the operating system which would allow the firearm to be immediately discharged upon exit from an aquatic environment would be highly desirable.
A bolt carrier which could be utilized with LWRC International's “Firearm with Facility for Open-Bolt and Closed-Bolt Operation” (U.S. Pat. No. 7,806,039) without the use of tools to assemble/disassemble the rifle would be desirable to military and civilian owners who want the benefits offered by such a system.
It would be highly advantageous, therefore, to remedy the foregoing and other deficiencies inherent in the prior art.